drivers/media/v4l2-core/v4l2-device.c - maze/linux - Git at Google

 /*
     V4L2 device support.

     Copyright (C) 2008  Hans Verkuil <hverkuil@xs4all.nl>

     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.

     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */

 #include <linux/types.h>
 #include <linux/ioctl.h>
 #include <linux/module.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>
 #if defined(CONFIG_SPI)
 #include <linux/spi/spi.h>
 #endif
 #include <linux/videodev2.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-ctrls.h>

 int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
 {
 	if (v4l2_dev == NULL)
 		return -EINVAL;

 	INIT_LIST_HEAD(&v4l2_dev->subdevs);
 	spin_lock_init(&v4l2_dev->lock);
 	mutex_init(&v4l2_dev->ioctl_lock);
 	v4l2_prio_init(&v4l2_dev->prio);
 	kref_init(&v4l2_dev->ref);
 	get_device(dev);
 	v4l2_dev->dev = dev;
 	if (dev == NULL) {
 		/* If dev == NULL, then name must be filled in by the caller */
 		WARN_ON(!v4l2_dev->name[0]);
 		return 0;
 	}

 	/* Set name to driver name + device name if it is empty. */
 	if (!v4l2_dev->name[0])
 		snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
 			dev->driver->name, dev_name(dev));
 	if (!dev_get_drvdata(dev))
 		dev_set_drvdata(dev, v4l2_dev);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_register);

 static void v4l2_device_release(struct kref *ref)
 {
 	struct v4l2_device *v4l2_dev =
 		container_of(ref, struct v4l2_device, ref);

 	if (v4l2_dev->release)
 		v4l2_dev->release(v4l2_dev);
 }

 int v4l2_device_put(struct v4l2_device *v4l2_dev)
 {
 	return kref_put(&v4l2_dev->ref, v4l2_device_release);
 }
 EXPORT_SYMBOL_GPL(v4l2_device_put);

 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
 						atomic_t *instance)
 {
 	int num = atomic_inc_return(instance) - 1;
 	int len = strlen(basename);

 	if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
 		snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
 				"%s-%d", basename, num);
 	else
 		snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
 				"%s%d", basename, num);
 	return num;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_set_name);

 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
 {
 	if (v4l2_dev->dev == NULL)
 		return;

 	if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
 		dev_set_drvdata(v4l2_dev->dev, NULL);
 	put_device(v4l2_dev->dev);
 	v4l2_dev->dev = NULL;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);

 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
 {
 	struct v4l2_subdev *sd, *next;

 	if (v4l2_dev == NULL)
 		return;
 	v4l2_device_disconnect(v4l2_dev);

 	/* Unregister subdevs */
 	list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
 		v4l2_device_unregister_subdev(sd);
 #if IS_ENABLED(CONFIG_I2C)
 		if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
 			struct i2c_client *client = v4l2_get_subdevdata(sd);

 			/* We need to unregister the i2c client explicitly.
 			   We cannot rely on i2c_del_adapter to always
 			   unregister clients for us, since if the i2c bus
 			   is a platform bus, then it is never deleted. */
 			if (client)
 				i2c_unregister_device(client);
 			continue;
 		}
 #endif
 #if defined(CONFIG_SPI)
 		if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
 			struct spi_device *spi = v4l2_get_subdevdata(sd);

 			if (spi)
 				spi_unregister_device(spi);
 			continue;
 		}
 #endif
 	}
 }
 EXPORT_SYMBOL_GPL(v4l2_device_unregister);

 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 				struct v4l2_subdev *sd)
 {
 #if defined(CONFIG_MEDIA_CONTROLLER)
 	struct media_entity *entity = &sd->entity;
 #endif
 	int err;

 	/* Check for valid input */
 	if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
 		return -EINVAL;

 	/* Warn if we apparently re-register a subdev */
 	WARN_ON(sd->v4l2_dev != NULL);

 	if (!try_module_get(sd->owner))
 		return -ENODEV;

 	sd->v4l2_dev = v4l2_dev;
 	if (sd->internal_ops && sd->internal_ops->registered) {
 		err = sd->internal_ops->registered(sd);
 		if (err)
 			goto error_module;
 	}

 	/* This just returns 0 if either of the two args is NULL */
 	err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler, NULL);
 	if (err)
 		goto error_unregister;

 #if defined(CONFIG_MEDIA_CONTROLLER)
 	/* Register the entity. */
 	if (v4l2_dev->mdev) {
 		err = media_device_register_entity(v4l2_dev->mdev, entity);
 		if (err < 0)
 			goto error_unregister;
 	}
 #endif

 	spin_lock(&v4l2_dev->lock);
 	list_add_tail(&sd->list, &v4l2_dev->subdevs);
 	spin_unlock(&v4l2_dev->lock);

 	return 0;

 error_unregister:
 	if (sd->internal_ops && sd->internal_ops->unregistered)
 		sd->internal_ops->unregistered(sd);
 error_module:
 	module_put(sd->owner);
 	sd->v4l2_dev = NULL;
 	return err;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);

 static void v4l2_device_release_subdev_node(struct video_device *vdev)
 {
 	struct v4l2_subdev *sd = video_get_drvdata(vdev);
 	sd->devnode = NULL;
 	kfree(vdev);
 }

 int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
 {
 	struct video_device *vdev;
 	struct v4l2_subdev *sd;
 	int err;

 	/* Register a device node for every subdev marked with the
 	 * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 	 */
 	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 		if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
 			continue;

 		vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 		if (!vdev) {
 			err = -ENOMEM;
 			goto clean_up;
 		}

 		video_set_drvdata(vdev, sd);
 		strlcpy(vdev->name, sd->name, sizeof(vdev->name));
 		vdev->v4l2_dev = v4l2_dev;
 		vdev->fops = &v4l2_subdev_fops;
 		vdev->release = v4l2_device_release_subdev_node;
 		vdev->ctrl_handler = sd->ctrl_handler;
 		err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
 					      sd->owner);
 		if (err < 0) {
 			kfree(vdev);
 			goto clean_up;
 		}
 #if defined(CONFIG_MEDIA_CONTROLLER)
 		sd->entity.info.v4l.major = VIDEO_MAJOR;
 		sd->entity.info.v4l.minor = vdev->minor;
 #endif
 		sd->devnode = vdev;
 	}
 	return 0;

 clean_up:
 	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 		if (!sd->devnode)
 			break;
 		video_unregister_device(sd->devnode);
 	}

 	return err;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);

 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 {
 	struct v4l2_device *v4l2_dev;

 	/* return if it isn't registered */
 	if (sd == NULL || sd->v4l2_dev == NULL)
 		return;

 	v4l2_dev = sd->v4l2_dev;

 	spin_lock(&v4l2_dev->lock);
 	list_del(&sd->list);
 	spin_unlock(&v4l2_dev->lock);

 	if (sd->internal_ops && sd->internal_ops->unregistered)
 		sd->internal_ops->unregistered(sd);
 	sd->v4l2_dev = NULL;

 #if defined(CONFIG_MEDIA_CONTROLLER)
 	if (v4l2_dev->mdev)
 		media_device_unregister_entity(&sd->entity);
 #endif
 	video_unregister_device(sd->devnode);
 	module_put(sd->owner);
 }
 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
	/*
	V4L2 device support.

	Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#include <linux/types.h>
	#include <linux/ioctl.h>
	#include <linux/module.h>
	#include <linux/i2c.h>
	#include <linux/slab.h>
	#if defined(CONFIG_SPI)
	#include <linux/spi/spi.h>
	#endif
	#include <linux/videodev2.h>
	#include <media/v4l2-device.h>
	#include <media/v4l2-ctrls.h>

	int v4l2_device_register(struct device dev, struct v4l2_device v4l2_dev)
	{
	if (v4l2_dev == NULL)
	return -EINVAL;

	INIT_LIST_HEAD(&v4l2_dev->subdevs);
	spin_lock_init(&v4l2_dev->lock);
	mutex_init(&v4l2_dev->ioctl_lock);
	v4l2_prio_init(&v4l2_dev->prio);
	kref_init(&v4l2_dev->ref);
	get_device(dev);
	v4l2_dev->dev = dev;
	if (dev == NULL) {
	/* If dev == NULL, then name must be filled in by the caller */
	WARN_ON(!v4l2_dev->name[0]);
	return 0;
	}

	/* Set name to driver name + device name if it is empty. */
	if (!v4l2_dev->name[0])
	snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
	dev->driver->name, dev_name(dev));
	if (!dev_get_drvdata(dev))
	dev_set_drvdata(dev, v4l2_dev);
	return 0;
	}
	EXPORT_SYMBOL_GPL(v4l2_device_register);

	static void v4l2_device_release(struct kref *ref)
	{
	struct v4l2_device *v4l2_dev =
	container_of(ref, struct v4l2_device, ref);

	if (v4l2_dev->release)
	v4l2_dev->release(v4l2_dev);
	}

	int v4l2_device_put(struct v4l2_device *v4l2_dev)
	{
	return kref_put(&v4l2_dev->ref, v4l2_device_release);
	}
	EXPORT_SYMBOL_GPL(v4l2_device_put);

	int v4l2_device_set_name(struct v4l2_device v4l2_dev, const char basename,
	atomic_t *instance)
	{
	int num = atomic_inc_return(instance) - 1;
	int len = strlen(basename);

	if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
	snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
	"%s-%d", basename, num);
	else
	snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
	"%s%d", basename, num);
	return num;
	}
	EXPORT_SYMBOL_GPL(v4l2_device_set_name);

	void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
	{
	if (v4l2_dev->dev == NULL)
	return;

	if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
	dev_set_drvdata(v4l2_dev->dev, NULL);
	put_device(v4l2_dev->dev);
	v4l2_dev->dev = NULL;
	}
	EXPORT_SYMBOL_GPL(v4l2_device_disconnect);

	void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
	{
	struct v4l2_subdev sd, next;

	if (v4l2_dev == NULL)
	return;
	v4l2_device_disconnect(v4l2_dev);

	/* Unregister subdevs */
	list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
	v4l2_device_unregister_subdev(sd);
	#if IS_ENABLED(CONFIG_I2C)
	if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
	struct i2c_client *client = v4l2_get_subdevdata(sd);

	/* We need to unregister the i2c client explicitly.
	We cannot rely on i2c_del_adapter to always
	unregister clients for us, since if the i2c bus
	is a platform bus, then it is never deleted. */
	if (client)
	i2c_unregister_device(client);
	continue;
	}
	#endif
	#if defined(CONFIG_SPI)
	if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
	struct spi_device *spi = v4l2_get_subdevdata(sd);

	if (spi)
	spi_unregister_device(spi);
	continue;
	}
	#endif
	}
	}
	EXPORT_SYMBOL_GPL(v4l2_device_unregister);

	int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
	struct v4l2_subdev *sd)
	{
	#if defined(CONFIG_MEDIA_CONTROLLER)
	struct media_entity *entity = &sd->entity;
	#endif
	int err;

	/* Check for valid input */
	if (v4l2_dev == NULL \|\| sd == NULL \|\| !sd->name[0])
	return -EINVAL;

	/* Warn if we apparently re-register a subdev */
	WARN_ON(sd->v4l2_dev != NULL);

	if (!try_module_get(sd->owner))
	return -ENODEV;

	sd->v4l2_dev = v4l2_dev;
	if (sd->internal_ops && sd->internal_ops->registered) {
	err = sd->internal_ops->registered(sd);
	if (err)
	goto error_module;
	}

	/* This just returns 0 if either of the two args is NULL */
	err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler, NULL);
	if (err)
	goto error_unregister;

	#if defined(CONFIG_MEDIA_CONTROLLER)
	/* Register the entity. */
	if (v4l2_dev->mdev) {
	err = media_device_register_entity(v4l2_dev->mdev, entity);
	if (err < 0)
	goto error_unregister;
	}
	#endif

	spin_lock(&v4l2_dev->lock);
	list_add_tail(&sd->list, &v4l2_dev->subdevs);
	spin_unlock(&v4l2_dev->lock);

	return 0;

	error_unregister:
	if (sd->internal_ops && sd->internal_ops->unregistered)
	sd->internal_ops->unregistered(sd);
	error_module:
	module_put(sd->owner);
	sd->v4l2_dev = NULL;
	return err;
	}
	EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);

	static void v4l2_device_release_subdev_node(struct video_device *vdev)
	{
	struct v4l2_subdev *sd = video_get_drvdata(vdev);
	sd->devnode = NULL;
	kfree(vdev);
	}

	int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
	{
	struct video_device *vdev;
	struct v4l2_subdev *sd;
	int err;

	/* Register a device node for every subdev marked with the
	* V4L2_SUBDEV_FL_HAS_DEVNODE flag.
	*/
	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
	if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
	continue;

	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
	if (!vdev) {
	err = -ENOMEM;
	goto clean_up;
	}

	video_set_drvdata(vdev, sd);
	strlcpy(vdev->name, sd->name, sizeof(vdev->name));
	vdev->v4l2_dev = v4l2_dev;
	vdev->fops = &v4l2_subdev_fops;
	vdev->release = v4l2_device_release_subdev_node;
	vdev->ctrl_handler = sd->ctrl_handler;
	err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
	sd->owner);
	if (err < 0) {
	kfree(vdev);
	goto clean_up;
	}
	#if defined(CONFIG_MEDIA_CONTROLLER)
	sd->entity.info.v4l.major = VIDEO_MAJOR;
	sd->entity.info.v4l.minor = vdev->minor;
	#endif
	sd->devnode = vdev;
	}
	return 0;

	clean_up:
	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
	if (!sd->devnode)
	break;
	video_unregister_device(sd->devnode);
	}

	return err;
	}
	EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);

	void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
	{
	struct v4l2_device *v4l2_dev;

	/* return if it isn't registered */
	if (sd == NULL \|\| sd->v4l2_dev == NULL)
	return;

	v4l2_dev = sd->v4l2_dev;

	spin_lock(&v4l2_dev->lock);
	list_del(&sd->list);
	spin_unlock(&v4l2_dev->lock);

	if (sd->internal_ops && sd->internal_ops->unregistered)
	sd->internal_ops->unregistered(sd);
	sd->v4l2_dev = NULL;

	#if defined(CONFIG_MEDIA_CONTROLLER)
	if (v4l2_dev->mdev)
	media_device_unregister_entity(&sd->entity);
	#endif
	video_unregister_device(sd->devnode);
	module_put(sd->owner);
	}
	EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);